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authorRickard Green <[email protected]>2016-08-29 17:52:10 +0200
committerRickard Green <[email protected]>2016-08-29 17:52:10 +0200
commit928d74ffa09bd56652d9390b02fa51ef51d71d51 (patch)
treebfb9cd9e76d4ef766dbcd999adf16c700350b399 /erts/preloaded/src
parent69d442f8afc67aef33c70d68d7eaab2bdad1400f (diff)
parent9d0638216d35ca0f21c1eea20f8daa3992ac4f71 (diff)
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Merge branch 'rickard/fun-purge-bug/OTP-13809' and 'rickard/new-purge-strategy/OTP-13833' into maint
* rickard/fun-purge-bug/OTP-13809: Fix purge of code Reclaim literal area after purge has completed Separate literal area from code Conflicts: erts/doc/src/erlang.xml erts/emulator/beam/beam_bif_load.c erts/emulator/beam/erl_init.c erts/preloaded/ebin/init.beam
Diffstat (limited to 'erts/preloaded/src')
-rw-r--r--erts/preloaded/src/Makefile3
-rw-r--r--erts/preloaded/src/erts.app.src2
-rw-r--r--erts/preloaded/src/erts_code_purger.erl141
-rw-r--r--erts/preloaded/src/erts_internal.erl23
-rw-r--r--erts/preloaded/src/erts_literal_area_collector.erl113
-rw-r--r--erts/preloaded/src/init.erl4
6 files changed, 246 insertions, 40 deletions
diff --git a/erts/preloaded/src/Makefile b/erts/preloaded/src/Makefile
index 4a447d3a09..df4645070b 100644
--- a/erts/preloaded/src/Makefile
+++ b/erts/preloaded/src/Makefile
@@ -44,7 +44,8 @@ PRE_LOADED_ERL_MODULES = \
erts_code_purger \
erlang \
erts_internal \
- erl_tracer
+ erl_tracer \
+ erts_literal_area_collector
PRE_LOADED_BEAM_MODULES = \
prim_eval
diff --git a/erts/preloaded/src/erts.app.src b/erts/preloaded/src/erts.app.src
index e18da28905..7ab06164b4 100644
--- a/erts/preloaded/src/erts.app.src
+++ b/erts/preloaded/src/erts.app.src
@@ -37,7 +37,7 @@
{registered, []},
{applications, []},
{env, []},
- {runtime_dependencies, ["stdlib-3.0", "kernel-5.0", "sasl-3.0"]}
+ {runtime_dependencies, ["stdlib-3.0", "kernel-5.0", "sasl-3.0.1"]}
]}.
%% vim: ft=erlang
diff --git a/erts/preloaded/src/erts_code_purger.erl b/erts/preloaded/src/erts_code_purger.erl
index d1e64342e0..ee4fcedd2d 100644
--- a/erts/preloaded/src/erts_code_purger.erl
+++ b/erts/preloaded/src/erts_code_purger.erl
@@ -22,7 +22,7 @@
%% Purpose : Implement system process erts_code_purger
%% to handle code module purging.
--export([start/0, purge/1, soft_purge/1]).
+-export([start/0, purge/1, soft_purge/1, pending_purge_lambda/3]).
-spec start() -> term().
start() ->
@@ -40,10 +40,43 @@ loop() ->
Res = do_soft_purge(Mod),
From ! {reply, soft_purge, Res, Ref};
+ {test_purge, Mod, From, Type, Ref} when is_atom(Mod), is_pid(From) ->
+ do_test_purge(Mod, From, Type, Ref);
+
_Other -> ignore
end,
loop().
+%%
+%% Processes that tries to call a fun that belongs to
+%% a module that currently is being purged will end
+%% up here (pending_purge_lambda) in a suspended state.
+%% When the purge operation completes or aborts (soft
+%% purge that failed) these processes will be resumed.
+%%
+pending_purge_lambda(_Module, Fun, Args) ->
+ %%
+ %% When the process is resumed, the following
+ %% scenarios exist:
+ %% * The code that the fun refers to is still
+ %% there due to a failed soft purge. The
+ %% call to the fun will succeed via apply/2.
+ %% * The code was purged, and a current version
+ %% of the module is loaded which does not
+ %% contain this fun. The call will result
+ %% in an exception being raised.
+ %% * The code was purged, and no current
+ %% version of the module is loaded. An attempt
+ %% to load the module (via the error_handler)
+ %% will be made. This may or may not succeed.
+ %% If the module is loaded, it may or may
+ %% not contain the fun. The call will
+ %% succeed if the error_handler was able
+ %% to load the module and loaded module
+ %% contains this fun; otherwise, an exception
+ %% will be raised.
+ %%
+ apply(Fun, Args).
%% purge(Module)
%% Kill all processes running code from *old* Module, and then purge the
@@ -60,16 +93,14 @@ purge(Mod) when is_atom(Mod) ->
Result
end.
-
do_purge(Mod) ->
- case erts_internal:copy_literals(Mod, true) of
- false ->
- {false, false};
- true ->
- DidKill = check_proc_code(erlang:processes(), Mod, true),
- true = erts_internal:copy_literals(Mod, false),
- WasPurged = erts_internal:purge_module(Mod),
- {WasPurged, DidKill}
+ case erts_internal:purge_module(Mod, prepare) of
+ false ->
+ {false, false};
+ true ->
+ DidKill = check_proc_code(erlang:processes(), Mod, true),
+ true = erts_internal:purge_module(Mod, complete),
+ {true, DidKill}
end.
%% soft_purge(Module)
@@ -85,21 +116,17 @@ soft_purge(Mod) ->
Result
end.
-
do_soft_purge(Mod) ->
- case erts_internal:copy_literals(Mod, true) of
+ case erts_internal:purge_module(Mod, prepare) of
false ->
true;
true ->
- DoPurge = check_proc_code(erlang:processes(), Mod, false),
- true = erts_internal:copy_literals(Mod, false),
- case DoPurge of
- false ->
- false;
- true ->
- erts_internal:purge_module(Mod),
- true
- end
+ Res = check_proc_code(erlang:processes(), Mod, false),
+ erts_internal:purge_module(Mod,
+ case Res of
+ false -> abort;
+ true -> complete
+ end)
end.
%%
@@ -283,8 +310,7 @@ cpc_sched_kill(Pid,
cpc_request(#cpc_static{tag = Tag, module = Mod}, Pid, AllowGc) ->
erts_internal:check_process_code(Pid, Mod, [{async, {Tag, Pid, AllowGc}},
- {allow_gc, AllowGc},
- {copy_literals, true}]).
+ {allow_gc, AllowGc}]).
cpc_request_gc(CpcS, [Pid|Pids]) ->
cpc_request(CpcS, Pid, true),
@@ -297,3 +323,72 @@ cpc_init(CpcS, [Pid|Pids], NoReqs) ->
cpc_init(CpcS, Pids, NoReqs+1).
% end of check_proc_code() implementation.
+
+%%
+%% FOR TESTING ONLY
+%%
+%% do_test_purge() is for testing only. The purge is done
+%% as usual, but the tester can control when to enter the
+%% specific phases.
+%%
+do_test_purge(Mod, From, Type, Ref) when Type == true; Type == false ->
+ Mon = erlang:monitor(process, From),
+ Res = case Type of
+ true -> do_test_hard_purge(Mod, From, Ref, Mon);
+ false -> do_test_soft_purge(Mod, From, Ref, Mon)
+ end,
+ From ! {test_purge, Res, Ref},
+ erlang:demonitor(Mon, [flush]),
+ ok;
+do_test_purge(_, _, _, _) ->
+ ok.
+
+do_test_soft_purge(Mod, From, Ref, Mon) ->
+ PrepRes = erts_internal:purge_module(Mod, prepare),
+ TestRes = test_progress(started, From, Mon, Ref, ok),
+ case PrepRes of
+ false ->
+ _ = test_progress(continued, From, Mon, Ref, TestRes),
+ true;
+ true ->
+ Res = check_proc_code(erlang:processes(), Mod, false),
+ _ = test_progress(continued, From, Mon, Ref, TestRes),
+ erts_internal:purge_module(Mod,
+ case Res of
+ false -> abort;
+ true -> complete
+ end)
+ end.
+
+do_test_hard_purge(Mod, From, Ref, Mon) ->
+ PrepRes = erts_internal:purge_module(Mod, prepare),
+ TestRes = test_progress(started, From, Mon, Ref, ok),
+ case PrepRes of
+ false ->
+ _ = test_progress(continued, From, Mon, Ref, TestRes),
+ {false, false};
+ true ->
+ DidKill = check_proc_code(erlang:processes(), Mod, true),
+ _ = test_progress(continued, From, Mon, Ref, TestRes),
+ true = erts_internal:purge_module(Mod, complete),
+ {true, DidKill}
+ end.
+
+test_progress(_State, _From, _Mon, _Ref, died) ->
+ %% Test process died; continue so we wont
+ %% leave the system in an inconsistent
+ %% state...
+ died;
+test_progress(started, From, Mon, Ref, ok) ->
+ From ! {started, Ref},
+ receive
+ {'DOWN', Mon, process, From, _} -> died;
+ {continue, Ref} -> ok
+ end;
+test_progress(continued, From, Mon, Ref, ok) ->
+ From ! {continued, Ref},
+ receive
+ {'DOWN', Mon, process, From, _} -> died;
+ {complete, Ref} -> ok
+ end.
+
diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl
index 2459ea2a2c..2a6d626279 100644
--- a/erts/preloaded/src/erts_internal.erl
+++ b/erts/preloaded/src/erts_internal.erl
@@ -41,8 +41,8 @@
-export([request_system_task/3]).
-export([check_process_code/3]).
--export([copy_literals/2]).
--export([purge_module/1]).
+-export([release_literal_area_switch/0]).
+-export([purge_module/2]).
-export([flush_monitor_messages/3]).
@@ -211,7 +211,6 @@ request_system_task(_Pid, _Prio, _Request) ->
erlang:nif_error(undefined).
-define(ERTS_CPC_ALLOW_GC, (1 bsl 0)).
--define(ERTS_CPC_COPY_LITERALS, (1 bsl 1)).
-spec check_process_code(Module, Flags) -> boolean() when
Module :: module(),
@@ -223,7 +222,7 @@ check_process_code(_Module, _Flags) ->
Pid :: pid(),
Module :: module(),
RequestId :: term(),
- Option :: {async, RequestId} | {allow_gc, boolean()} | {copy_literals, boolean()},
+ Option :: {async, RequestId} | {allow_gc, boolean()},
OptionList :: [Option],
CheckResult :: boolean() | aborted.
check_process_code(Pid, Module, OptionList) ->
@@ -265,8 +264,6 @@ get_cpc_opts([{async, _ReqId} = AsyncTuple | Options], _OldAsync, Flags) ->
get_cpc_opts(Options, AsyncTuple, Flags);
get_cpc_opts([{allow_gc, AllowGC} | Options], Async, Flags) ->
get_cpc_opts(Options, Async, cpc_flags(Flags, ?ERTS_CPC_ALLOW_GC, AllowGC));
-get_cpc_opts([{copy_literals, CopyLit} | Options], Async, Flags) ->
- get_cpc_opts(Options, Async, cpc_flags(Flags, ?ERTS_CPC_COPY_LITERALS, CopyLit));
get_cpc_opts([], Async, Flags) ->
{Async, Flags}.
@@ -275,15 +272,15 @@ cpc_flags(OldFlags, Bit, true) ->
cpc_flags(OldFlags, Bit, false) ->
OldFlags band (bnot Bit).
--spec copy_literals(Module,Bool) -> 'true' | 'false' | 'aborted' when
- Module :: module(),
- Bool :: boolean().
-copy_literals(_Mod, _Bool) ->
+-spec release_literal_area_switch() -> 'true' | 'false'.
+
+release_literal_area_switch() ->
erlang:nif_error(undefined).
--spec purge_module(Module) -> boolean() when
- Module :: module().
-purge_module(_Module) ->
+-spec purge_module(Module, Op) -> boolean() when
+ Module :: module(),
+ Op :: 'prepare' | 'abort' | 'complete'.
+purge_module(_Module, _Op) ->
erlang:nif_error(undefined).
-spec system_check(Type) -> 'ok' when
diff --git a/erts/preloaded/src/erts_literal_area_collector.erl b/erts/preloaded/src/erts_literal_area_collector.erl
new file mode 100644
index 0000000000..3befad8dfb
--- /dev/null
+++ b/erts/preloaded/src/erts_literal_area_collector.erl
@@ -0,0 +1,113 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2016. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+-module(erts_literal_area_collector).
+
+-export([start/0]).
+
+%% Currently we only allow two outstanding literal
+%% copying jobs that garbage collect in order to
+%% copy the literals. Maybe we could allow more
+%% than two outstanding processes, but for now we
+%% play it safe...
+-define(MAX_GC_OUTSTND, 2).
+
+%%
+%% The erts_literal_area_collector is started at
+%% VM boot by the VM. It is a spawned as a system
+%% process, i.e, the whole VM will terminate if
+%% this process terminates.
+%%
+start() ->
+ process_flag(trap_exit, true),
+ msg_loop(undefined, 0, 0, []).
+
+%%
+%% The VM will send us a 'copy_literals' message
+%% when it has a new literal area that needs to
+%% be handled is added. We will also be informed
+%% about more areas when we call
+%% erts_internal:release_literal_area_switch().
+%%
+msg_loop(Area, Outstnd, GcOutstnd, NeedGC) ->
+ receive
+
+ %% A new area to handle has arrived...
+ copy_literals when Outstnd == 0 ->
+ switch_area();
+
+ %% Process (_Pid) has completed the request...
+ {copy_literals, {Area, _GcAllowed, _Pid}, ok} when Outstnd == 1 ->
+ switch_area(); %% Last process completed...
+ {copy_literals, {Area, false, _Pid}, ok} ->
+ msg_loop(Area, Outstnd-1, GcOutstnd, NeedGC);
+ {copy_literals, {Area, true, _Pid}, ok} when NeedGC == [] ->
+ msg_loop(Area, Outstnd-1, GcOutstnd-1, []);
+ {copy_literals, {Area, true, _Pid}, ok} ->
+ send_copy_req(hd(NeedGC), Area, true),
+ msg_loop(Area, Outstnd-1, GcOutstnd, tl(NeedGC));
+
+ %% Process (Pid) failed to complete the request
+ %% since it needs to garbage collect in order to
+ %% complete the request...
+ {copy_literals, {Area, false, Pid}, need_gc} when GcOutstnd < ?MAX_GC_OUTSTND ->
+ send_copy_req(Pid, Area, true),
+ msg_loop(Area, Outstnd, GcOutstnd+1, NeedGC);
+ {copy_literals, {Area, false, Pid}, need_gc} ->
+ msg_loop(Area, Outstnd, GcOutstnd, [Pid|NeedGC]);
+
+ %% Not handled message regarding the area that we
+ %% currently are working with. Crash the VM so
+ %% we notice this bug...
+ {copy_literals, {Area, _, _}, _} = Msg when erlang:is_reference(Area) ->
+ exit({not_handled_message, Msg});
+
+ %% Unexpected garbage message. Get rid of it...
+ _Ignore ->
+ msg_loop(Area, Outstnd, GcOutstnd, NeedGC)
+
+ end.
+
+switch_area() ->
+ Res = erts_internal:release_literal_area_switch(),
+ erlang:garbage_collect(), %% Almost no live data now...
+ case Res of
+ false ->
+ %% No more areas to handle...
+ msg_loop(undefined, 0, 0, []);
+ true ->
+ %% Send requests to all processes to copy
+ %% all live data they have referring to the
+ %% literal area that is to be released...
+ Area = make_ref(),
+ Outstnd = send_copy_reqs(erlang:processes(), Area, false),
+ msg_loop(Area, Outstnd, 0, [])
+ end.
+
+send_copy_reqs(Ps, Area, GC) ->
+ send_copy_reqs(Ps, Area, GC, 0).
+
+send_copy_reqs([], _Area, _GC, N) ->
+ N;
+send_copy_reqs([P|Ps], Area, GC, N) ->
+ send_copy_req(P, Area, GC),
+ send_copy_reqs(Ps, Area, GC, N+1).
+
+send_copy_req(P, Area, GC) ->
+ erts_internal:request_system_task(P, normal, {copy_literals, {Area, GC, P}, GC}).
diff --git a/erts/preloaded/src/init.erl b/erts/preloaded/src/init.erl
index 67929c53c2..962528f7ab 100644
--- a/erts/preloaded/src/init.erl
+++ b/erts/preloaded/src/init.erl
@@ -669,9 +669,9 @@ unload(_) ->
do_unload(sub([heart|erlang:pre_loaded()],erlang:loaded())).
do_unload([M|Mods]) ->
- catch erts_internal:purge_module(M),
+ catch erlang:purge_module(M),
catch erlang:delete_module(M),
- catch erts_internal:purge_module(M),
+ catch erlang:purge_module(M),
do_unload(Mods);
do_unload([]) ->
purge_all_hipe_refs(),